Interest in medicinal plants as a re-emerging health aid has been fuelled by the rising costs of prescription drugs in the maintenance
of personal health and well-being, and the bioprospecting of new plant-derived drugs. Several issues as well as a range of interests and activities in a number of countries are dealt with. Based on current
research and financial investments, medicinal plants will, seemingly, continue to play an important role as an health aid.

Medicinal plants, since
times immemorial, have been used in virtually all
cultures as a source of medicine. The widespread use of
herbal remedies and healthcare preparations, as those
described in ancient texts such as the Vedas and the
Bible, and obtained from commonly used traditional herbs
and medicinal plants, has been traced to the occurrence
of natural products with medicinal properties.

The use of traditional
medicine and medicinal plants in most developing
countries, as a normative basis for the maintenance of
good health, has been widely observed (UNESCO, 1996). Furthermore, an increasing
reliance on the use of medicinal plants in the
industrialised societies has been traced to the
extraction and development of several drugs and
chemotherapeutics from these plants as well as from
traditionally used rural herbal remedies (UNESCO, 1998). Moreover, in these societies,
herbal remedies have become more popular in the treatment
of minor ailments, and also on account of the increasing
costs of personal health maintenance. Indeed, the market
and public demand has been so great that there is a great
risk that many medicinal plants today, face either
extinction or loss of genetic diversity.

Background

Medicine, in several
developing countries, using local traditions and beliefs,
is still the mainstay of health care. As defined by WHO,
health is a state of complete physical, mental, and
social well being and not merely the absence of disease
or infirmity.

The practise of
traditional medicine is widespread in China, India,
Japan, Pakistan,
Sri Lanka and Thailand. In China about 40% of the total
medicinal consumption is attributed to traditional tribal
medicines. In Thailand, herbal medicines make use of
legumes encountered in the Caesalpiniaceae, the Fabaceae,
and the Mimosaceae. In the mid-90s, it is
estimated that receipts of more than US$2.5 billion have
resulted from the sales of herbal medicines. And, in
Japan, herbal medicinal preparations are more in demand
than mainstream pharmaceutical products.

Africa is a rich source of
medicinal plants. Perhaps, the best known species is Phytolacca
dodecandra. Extracts of the plant, commonly known as endod,
are used as an effective molluscicide to control
schistosomiasis (Lemma, 1991). Other notable examples are Catharanthus
roseus, which yields anti-tumour agents such as
vinblastine and vincristine; and Ricinus communis,
which yields the laxative--castor oil. In Botswana,
Lesotho, Namibia and South Africa, Harpagophytum
procumbens is produced as a crude drug for export.
Similarly, Hibiscus sabdariffa is exported from
Sudan and Egypt. Other exports are Pausinystalia
yohimbe from Cameroon, Nigeria and Rwanda, which
yields yohimbine; and Rauwolfia vomitoria,
from Madagascar, Mozambique and Zaire, which is exploited
to yield reserpine and ajmaline.

The use of medicinal
plants like Eupatorium perfoliatum (bonest), Podophyllum
peltatum (mayapple), and Panax quinquefolium
(ginseng) in the USA has long been associated with the
American Indians. These plants have also been appreciated
and recognised for their aesthetic and ornamental value.
In Central America medicinal plants have been widely used
- by the Maya Indians in Mexico, the Miskitos
and Sumus in Honduras and Nicaragua, the Pech,
Lencas, and Xicaques in Honduras, the Pipiles
in El Salvador, the Talamancas in Costa Rica, and
the Guaymis and Kunas in Panama.

In Europe, some 1500
species of medicinal and aromatic plants are widely used
in Albania, Bulgaria, Croatia, France, Germany, Hungary,
Poland, Spain, Turkey, and the United Kingdom. The
Maltese islands constitute an apt example where medicinal
plants are widely used in every day life as part of folk
medicinal remedies (Lanfranco, 1992).

Issues

Traditional and folklore
medicine bequeathed from generation to generation is rich
in domestic recipes and communal practice. Encompassing
concepts and methods for the protection and restoration
of health, traditional medicine has served as a fount of
alternative medicine, new pharmaceuticals, and healthcare
products. The best known examples of traditional
medicine, differing in concept and protocol, are
well-developed systems such as acupuncture and ayurvedic
medicine that have been widely used to conserve human
health in China and India.

Developed countries, in
recent times, are turning to the use of traditional
medicinal systems that involve the use of herbal drugs
and remedies. About 1400 herbal preparations are used
widely, according to a recent survey in Member States of
the European Union. Herbal preparations are popular and
are of significance in primary healthcare in Belgium,
France, Germany and the Netherlands. Such popularity of
healthcare plant-derived products has been traced to
their increasing acceptance and use in the cosmetic
industry as well as to increasing public costs in the
daily maintenance of personal health and well being.
Examples of such beauty-oriented therapeuticals are skin
tissue regenerators, anti-wrinkling agents and anti-age
creams. Most dermaceuticals are derived from algal
extracts that are rich in minerals and the vitamin B
group. Skincare products such as skin creams, skin
tonics, etc. derived from medicinal plants are grouped
together as dermaceuticals. Also, amongst the poor, cures
and drugs, derived from plants, constitute the main
source of healthcare products.

Gorman(1992) drew attention to the power of
Chinese folk medicinal potions in treating maladies from
eczema and malaria to respiratory disorders. In the quest
for new medicines to treat old and emergent diseases such
as malaria and AIDS, attention is now being given to
discovering the active ingredients encountered in the
treasury of over 5,000 Chinese herbs, plants and roots
that have been used routinely and traditionally. Quinghaosu
and Chaihu are two such examples. Whereas the
former, called artemisinin and obtained from Artemisia
annua is expected to yield, in the coming millennium,
a potent new class of antimalarials, the latter, obtained
from Bupleurum chinense and used as a popular
remedy for hepatitis is the focus of intense research by
the Japanese pharmaceutical industry. More recently, the
biochemistry of tianhuafen or cucumber is being
studied in the USA to decipher the identity of compound
Q, an extract used in China and credited with
remedial and relief properties in AIDS sufferers.

Medicinal plants are an
integral component of ethnoveterinary medicine. Farmers
and pastoralists in several countries use medicinal
plants in the maintenance and conservation of the
healthcare of livestock. Intestinal disorders in cows, in
Mexico, are treated with herbal extracts of Polakowskia
tacacco. Dietary supplements such as vitamin A in
poultry feeds in Uganda are supplied through enrichments
of amaranth (Amaranthus sp.). It is estimated that
medicinal plants, for several centuries, have been widely
used as a primary source of prevention and control of
livestock diseases. In fact, interest of such use in the
veterinary sector has resulted primarily from the
increasing cost of livestock maintenance and the
introduction of new technology in the production of
veterinary medicines and vaccines.

McGee (1998), surveying the use of spice and their medicinal
properties around the world, concluded that spices serve the adaptive purpose
of reducing food-borne disease. In reviewing relevant texts ranging from the
preservative properties of spices against food spoilage to the presence of antimicrobial
substances that lay claim to the elimination of pathogenic organisms in food
preparations, the case is made for a more objective analysis and study of the
medicinal properties of spices in victu rather than in victo.
A whole range of plant-derived dietary supplements, phytochemicals and pro-vitamins
that assist in maintaining good health and combating disease are now being described
as functional foods, nutriceuticals and nutraceuticals. Table 1 provides some
examples of national activities concerning medicinal plants in several developed
and developing countries.

Despite the increasing use
of medicinal plants, their future, seemingly, is being
threatened by complacency concerning their conservation.
Reserves of herbs and stocks of medicinal plants in
developing countries are diminishing and in danger of
extinction as a result of growing trade demands for
cheaper healthcare products and new plant-based
therapeutic markets in preference to more expensive
target-specific drugs and biopharmaceuticals. Such
concerns have stimulated positive legal and economic
interest.

Issues concerning intellectual property rights,
compensation for loss of finance-rich biodiversity resources, and the acquisition
and safeguarding of traditional healthcare knowledge are no longer neglected.
Bioprospecting of new drugs from medicinal plants and the exploitation of unprotected
traditional knowledge in starting-up potentially new bioindustries are the focus
of new monitoring measures. Such concerns that call for adherence to and observation
of cultural and intellectual property rights have been addressed and enshrined
in the Chiang-Mai and Kari-Oca Declarations (Table 2). The first
countries to seriously tackle these issues are China and India. Indeed, programmes
dealing with medicinal plant conservation, cultivation, community involvement
and sustainable development being initiated elsewhere, could benefit immensely
from the Chinese and Indian experiences (World Bank, 1997).

Genetic biodiversity of
traditional medicinal herbs and plants is continuously
under the threat of extinction as a result of
growth-exploitation, environment-unfriendly harvesting
techniques, loss of growth habitats and unmonitored trade
of medicinal plants.

Medicinal herbs,
possessing penile potency properties and anti-cancer
principles are the focus of smuggling to import markets
in Germany, France, Switzerland, Japan, the U.K., and the
U.S.A. The best known example, in recent times, is that
of tetu lakda (Nothadoytes foetida).
Commonly encountered in southern India and Sri Lanka, the
herb is exploited as a source of anti-cancer drugs.

On the other hand, Adonis
vernalis, extinct in Italy and the Netherlands, is an
endangered species in Germany, Slovakia, Sweden and
Switzerland. Fortunately, to safeguard against such
practices and losses, guidelines and licensing concerning
the use of such plants are provided for in the Convention
on International Trade Endangered Species of Wild Flora
and Fauna (CITES).

The industrial uses of
medicinal plants are many. These range from traditional
medicines, herbal teas, and health foods such as
nutriceuticals to galenicals, phytopharmaceuticals and
industrially produced pharmaceuticals. Furthermore,
medicinal plants constitute a source of valuable foreign
exchange for most developing countries, as they are a
ready source of drugs such as quinine and reserpine; of
galenicals like tinctures and of intermediates (e.g.
diosgenin from Discorea sp.) in the production of
semi-synthetic drugs.

The world market for
plant-derived chemicals  pharmaceuticals,
fragrances, flavours, and colour ingredients, alone
exceeds several billion dollars per year. Classic
examples of phytochemicals in biology and medicine
include taxol, vincristine, vinblastine, colchicine as
well as the Chinese antimalarial - artemisinin, and the
Indian ayurdevic drug-forkolin. Trade in medicinal
plants is growing in volume and in exports. It is
estimated that the global trade in medicinal plants is
US$800 million per year.

The botanical market,
inclusive of herbs and medicinal plants, in the USA, is
estimated, at retail, at approximately US$1.6 billion
p.a. China with exports of over 120,000 tonnes p.a., and
India with some 32,000 tonnes p.a. dominate the
international markets. It is estimated that Europe,
annually, imports about 400,000 t of medicinal plants
with an average market value of US$ 1 billion from Africa
and Asia. A growing awareness of this new contributor to
the foreign-exchange reserves of several national
treasuries is beginning to emerge. To satisfy growing
market demands, surveys are being conducted to unearth
new plant sources of herbal remedies and medicines.

In several industrialised
societies, plant-derived prescription drugs constitute an
element in the maintenance of health. Medicinal plants
are an integral component of research developments in the
pharmaceutical industry. Such research focuses on the
isolation and direct use of active medicinal
constituents, or on the development of semi-synthetic
drugs, or still again on the active screening of natural
products to yield synthetic pharmacologically-active
compounds. In Germany, for example, over 1500 plant
species encountered in some 200 families and 800 genera
have been processed into medicinal products. In South
Africa, likewise, some 500 species are commercialised
trade products. Today, Bulgaria, Germany and Poland are
recognised as major exporters of plant-based medicinal
products.

The development and
commercialisation of medicinal plant-based bioindustries
in the developing countries is dependent upon the
availability of facilities and information concerning
upstream and downstream bioprocessing, extraction,
purification, and marketing of the industrial potential
of medicinal plants. Absence of such infrastructure
compounded by lack of governmental interest and financial
support restricts the evolution of traditional herbal
extracts into authenticated market products. Furthermore
the absence of modernised socio-economic and public
healthcare systems reinforces reliance of rural and
lower-income urban populations on the use of traditional
medicinal herbs and plants as complementary aids to
routine pharmaceutical market products.

Saint-Johns wort known as Johanniskrant in German
for centuries has been used to treat people with mild and
moderate depression without the side effects of Prozac.
Widely sold in Germany and other European countries, and
awaiting official approval by the US Food and Drug
Administration, Saint-Johns wort is being regarded
as a serious rival to Prozac (Andrews, 1997
).

Medicinal plants can make
an important contribution to the WHO goal to ensure, by
the year 2000, that all peoples, worldwide, will lead a
sustainable socio-economic productive life. The Centre
for Science and Technology of the Non-Aligned and other
Developing Countries in India organised an international
workshop on Tissue Culture of Economic Plants in
April, 1994, as a means of using modern biotechnological
techniques to nurture and conserve medicinal plants.

In late 1997, the World Bank, within the framework of the
Global Environmental Facility, provided a US$ 4.5 million
grant for the Sri Lanka Conservation of Medicinal
Plants Project which focuses on the conservation of
medicinal plant populations, their habitats, and their
sustainable use in Medicinal Plant Conservation Areas
(MPCAs). Inventories with emphasis on the management,
research and conservation of rare and endangered species
of medicinal plants are the main programmes at MPCAs at
Ritigala, Naula, Rajawaka, Kanneliya, and Bibile.

Aspects of policy and research concerning the cultivation
of non-tropical and tropical medicinal plants and their genetic improvement;
their conservation in botanical gardens; their storage in liquid nitrogen; their
economic potential in international pharmaceutical trade; and their vulnerability
to over-exploitation and extinction have been dealt with authoritatively (Akerele et al, 1991; Chadwick and Marsh, 1994). Moreover, such concerns and issues are addressed
through a variety of programme activities and projects conducted, and promoted
by several international, regional, and non-governmental organisations (
Table
3).

Concluding remarks

Recent and renewed
interest in medicinal plants coupled to developments in
information technology has fuelled an explosion in the
range and content of electronic information concerning
medicinal plants as a re-emergent health aid. Bhat (1997) recently reviewed diverse sources
of such information in traditional abstracting services
as well as in a variety of online electronic databases.
As a result of such developments, access to indigenous
peoples and cultures concerning medicinal plants are
greatly facilitated. Furthermore, the active
participation of such natural custodians and
practitioners of valuable knowledge is guaranteed in the
generation of research focussing on screening programmes
dealing with the isolation of bioactive principles and
the development of new drugs.

Lemma, A.
(1991). The Potentials and Challenges of Endod, the
Ethiopian Soapberry Plant for Control of Schistosomiasis.
In: Science in Africa: Achievements and Prospects,
American Association for the Advancement of Sciences
(AAAS), Washington, D.C., USA.